Removed cloning from sass_util functions.
Removed more cloning that doesn't cause test failures.
Remove more cloning based on sass-spec testing.
First pass at rewriting lcs to use ComplexSelectorDeque instead of Node. LCS was showing up in Instruments as taking a long time. It turned out that it was due to parentSuperselector, which had to call nodeToComplexSelector a lot. This allocated new objects each time, which was slow. If we use Complex_Selectors instead, we can avoid the memory allocations.
Finished testing and implementation of the unification scenarios in mergeFinalOps.
Removing unused unify code now that we're consistently using the unify_with methods in ast.cpp.
Remove the deep compare from trim since we can do a pointer comparision now that we don't clone in this method.
Clean up pass. Removing unused code. Renaming things more sensibly. Moving things to where they should be.
Merge remote-tracking branch 'origin/feature/perf-integration' into feature/extend-support